title: Ecological correlates of risk and incidence of West Nile virus in the United States.
abstract: West Nile virus, which was recently introduced to North America, is a mosquito-borne pathogen that infects a wide range of vertebrate hosts, including humans. Several species of birds appear to be the primary reservoir hosts, whereas other bird species, as well as other vertebrate species, can be infected but are less competent reservoirs. One hypothesis regarding the transmission dynamics of West Nile virus suggests that high bird diversity reduces West Nile virus transmission because mosquito blood-meals are distributed across a wide range of bird species, many of which have low reservoir competence. One mechanism by which this hypothesis can operate is that high-diversity bird communities might have lower community-competence, defined as the sum of the product of each species' abundance and its reservoir competence index value. Additional hypotheses posit that West Nile virus transmission will be reduced when either: (1) abundance of mosquito vectors is low; or (2) human population density is low. We assessed these hypotheses at two spatial scales: a regional scale near Saint Louis, MO, and a national scale (continental USA). We found that prevalence of West Nile virus infection in mosquito vectors and in humans increased with decreasing bird diversity and with increasing reservoir competence of the bird community. Our results suggest that conservation of avian diversity might help ameliorate the current West Nile virus epidemic in the USA.
authors.affiliation: Department of Biology, Washington University, One Brookings Drive, Campus Box 1137, Saint Louis, MO, 63130, USA. ballan@wustl.edu
authors.forename: Brian F
authors.initials: BF
authors.lastname: Allan
authors.forename: R Brian
authors.initials: RB
authors.lastname: Langerhans
authors.forename: Wade A
authors.initials: WA
authors.lastname: Ryberg
authors.forename: William J
authors.initials: WJ
authors.lastname: Landesman
authors.forename: Nicholas W
authors.initials: NW
authors.lastname: Griffin
authors.forename: Rachael S
authors.initials: RS
authors.lastname: Katz
authors.forename: Brad J
authors.initials: BJ
authors.lastname: Oberle
authors.forename: Michele R
authors.initials: MR
authors.lastname: Schutzenhofer
authors.forename: Kristina N
authors.initials: KN
authors.lastname: Smyth
authors.forename: Annabelle
authors.initials: A
authors.lastname: de St Maurice
authors.forename: Larry
authors.initials: L
authors.lastname: Clark
authors.forename: Kevin R
authors.initials: KR
authors.lastname: Crooks
authors.forename: Daniel E
authors.initials: DE
authors.lastname: Hernandez
authors.forename: Robert G
authors.initials: RG
authors.lastname: McLean
authors.forename: Richard S
authors.initials: RS
authors.lastname: Ostfeld
authors.forename: Jonathan M
authors.initials: JM
authors.lastname: Chase
mesh_terms: D000818:Animals; D044822:Biodiversity; D001717:Birds / Q000821:virology; D004196:Disease Outbreaks; D006801:Humans; D015994:Incidence; D011156:Population Density; D018570:Risk Assessment; D014481:United States; D014901:West Nile Fever / Q000453:epidemiology* / Q000635:transmission / Q000821:virology; D014902:West Nile virus / Q000302:isolation & purification